Reference values of spherical equivalent for predicting the onset and progression of myopia among children and adolescents in China.

Background/aims: To establish sex-specific and grade-specific reference values of cycloplegic spherical equivalent (SE) for predicting myopia onset and progression in Chinese children and adolescents.

Methods: Between 2020 and 2024, vision screening was conducted among 67 260 Chinese students spanning kindergarten to high school. Myopia was defined as a cycloplegic SE of ≤-0.50 diopters (D) and high myopia as ≤-6.00D. The lambda-mu-sigma method was used to estimate centiles of cycloplegic SE for -0.50D and -6.00D at each grade. Based on this, reference values for predicting future myopia and its progression to high myopia were determined for all grades.

Results: Among boys in grade 12 (the third year of high school), the estimated prevalence of myopia and high myopia was 82.4% and 11.6%, respectively. For boys in grades 0-11, the cycloplegic SE values at the 82.4th and 11.6th percentiles served as reference values to predict myopia and high myopia, respectively, in grade 12. For example, among senior kindergarten boys (grade 0), those with cycloplegic SE >1.54D (82.4th percentile) were predicted to remain non-myopic before grade 12, whereas those with SE >0.19D (11.6th percentile) were not expected to develop high myopia before grade 12.

Conclusions: Reference values for predicting myopia and high myopia among Chinese students were established, but these values may not be applicable to populations beyond China. Nevertheless, the proposed methods could be applied to settings where student myopia prevalence patterns remain relatively stable.